Hi Dave - Thank you for the nice welcome and the prompt reply.

I thought about sending a sample back to the States to be analysed, but I read that you have to keep the sample cold for it to be effective so shipping from here would be problematic. Is there a self testing kit that I could buy online that you would recommend? From all I've read, I'm pretty sure that tannins is our problem, but a test would be useful.

Thanks again for the help.